Engine



s; was

Jhm I Origihall Eiledi Feb". 4; 1959.

INVENTORS WILLIAM L.TENNEY 8 JOHN'E. EASTMAN 1965 w. TENNEY ETAL 3,

ENGINE Original Filed Feb. 4, 1959 4 Sheets-Sheet 4 FIG- 9 420 FIG-l3 0 370 F i G i :2: g 0 373 :20 J PROE "z 'z/ 35 [/4 C.V. "8 22 I27 V 5 H3 I FIG'IZ 35? L L358 35 INVENTORS WILLIAM L.TENNEY a 366 JOHN E. EASTMAN United States Patent and this application Feb. 27, 1962, Ser. No. 176,143

Claims. ((31. 60-14) This application relates to internal combustion engines, particularly such engines of the mass reaction type.

The present invention utilizes the reaction forces resulting from the inertial resistance of a solid reaction mass to obtain useful output from an internal combustion engine, particularly such engines constructed similarly to engines of the free piston type. Actually, both the piston and the cylinder members of the engine are free to move in space, within the confines of their respective mountings, in response to combustion of a charge in the power cylinder of the engine. One of these members is coupled directly to an output such that the output connection reciprocates with that member of the engine to which it is connected and applies useful power to a load. This power may be utilized to operate many difierent types of devices, typical examples being cutting devices wherein the reciprocating movement of the output-coupled member of the engine may be employed directly without amplification or transformation. The other freely movable member of the engine has substantial inertial resistance tomovement and thus provides the solid reaction mass, preferably being constructed so as to be relatively heavy with reference to the output-coupled member.

The piston and cylinder members of the engine, in addition to defining the power cylinder, and while being freely movable within the confines of their mountings, are both arranged to act upon a yieldable or compressible biasing means which is capable of storing and returning energy imparted thereto by the piston member and/or the cylinder member. Thus, for example, with an engine of this type operating on a two-stroke cycle, combustion of a charge produces a power stroke and an effective delivery of power through the output-coupled member of the engine in one direction, and in addition energy is stored in the biasing means during this power stroke and returned to the system as energy utilized partially for producing a compression stroke, with the piston compressing a charge in the cylinder in the usual manner, while the remaining energy is transferred through the output-coupled member to the output, providing an effective power delivery in the opposite direction from the output power of the power stroke of the engine. Therefore, useful energy is delivered at the output as a reciprocating movement powered in both directions, and the biasing means performs a function similar to the function of a flywheel in the familiar type of internal combustion engine having a fixed cylinder and a reciprocating piston connected through a crank to a rotating crankshaft.

The yieldable or compressible biasing means is of sufficient strength to absorb and return substantially all energy imparted thereto from the piston member and/ or the cylinder member in response to movement thereof by the force of combustion of a charge in the engine. Thus, the biasing means, which may preferably be in the form of a set of series-connected spring members which are progressively operatively engaged between the piston and cylinder members, will prevent impact between the piston and cylindrical members during the power stroke and the energy stored in the biasing means will be returned to the system partially to provide for compression of an additional charge in the power cylinder, and

"ice

partially to be transmitted as useful power through the output-coupled member. Accordingly, no impact occurs between the piston and cylinder members under normal operating conditions and no wear or destructive action results from such a cause. Thus, force is applied to the output-coupled. memberin both directions, first by the combustion of the charge, and then by the power stored in the biasing means during the combustion or power. stroke and returned subsequently to the system when the force of the combustion is dissipated.

The primary object of this invention is to provide a mass reaction internal combustion engine wherein output power is derived from the relative movement between a piston member and a cylinder member which movably react in opposite directions upon combustion of a charge in the engine, which is inherently easy to start, since one of the engine members which reacts to combustion is substantial-1y unloaded and free to move with the engine at rest, and thus the engine may be considered as under a no load condition at the time of starting in spite of the direct coupling to a load of the output-coupled member.

Another object of the invention is to provide a novel internal combustion engine which is of essentially simple low cost construction and easy to maintain, having few moving parts and a simple direct coupling to a load,

7 while retaining ease of starting and adaptability to accomapparent from the following description, the accompanying drawings and the appended In the drawings: FIGS. 1 and 2 are schematic representations of typical engine constructions in accordance with the invention;

claims.

FIG. 3 is a somewhat schematic vertical section through a one cylinder engine of a type shown generally in FIG. 1,

showing the piston and cylinder in relative position wherein the intake and exhaust ports are closed and the engine may be considered at rest;

FIG. 4 is a view similar to FIG. 3 illustrating the parts after relative movement resulting from combustion has occurred;

FIG. 5 is a section taken on lines 55 of FIG. 3;

FIG. 6 is a section taken on lines 6-6 of FIG. 3;

FIG. 7 is a view of a suitable fuel supply and air intake control valve which may be connected to the engine shown in FIGS. 3-6;

FIG.8 is a top plan view of a clipper bar-type of lawn mower to which the engine shown in FIGS. 36 has been attached, illustrating a typical application of the engine;

FIG. 9 is a detail view on an enlarged scale, partially in section, taken on line 99 of FIG. 8, and showing a suitable butter and guide structure for the engine on the lawn mower;

FIG. 10 is a section on an enlarged scale, taken on line 10-10 of FIG. 3, through the inlet for supplying starting pressure fiuid to the engine combustion chamber;

FIG. 11 is a schematic diagram of a suitable starting system for the engine;

FIGS. 12 and 13 are schematic diagrams of suitable ignition systems which may be used with the engine;

FIG. 14 is a schematic diagram of a novel starting system which may be used on the mowing machine.

The present invention relates to internal combustion mass reaction engines. Basically, an engine in accordance with the invention comprises a piston member and a cylinder member cooperating to define a power cylinder in cluding a combustion chamber into which a combustible charge is introduced in timed relation to relative movement between the piston and cylinder tending to compress a charge so supplied. The compression stroke basically is caused by a biasing means acting between the piston and cylinder in a direction tending to reduce the volume of the power cylinder, with this biasing means being of sufiicient strength to reverse relative movement of the piston and cylinder resulting from combustion of a charge in the combustion chamber while preventing impact between the piston and cylinder members under normal operating conditions. The power output is in the nature of a reciprocating stroke provided by a direct connection to either the piston or the cylinder, with the other being substantially freely movable relative to the output connected member.

For example, referring to the schematic showing in FIG. 1, the piston 10 is mounted for free movement in space within the cylinder 12, the free movement being confined of course in a direction axially of the cylinder member by the construction, and a biasing means in the form of a suitable spring 13 tends to oppose movement of these members resulting from combustion of a charge in the engine. The output connection is provided by an arm 17 bolted directly to cylinder member 12.

This application is a division of copending application Serial No. 791,107, filed February 4, 1959. Accordingly, reference is made to the parent application, now Patent No. 3,023,564, issued March 6, 1962, for a detailed explanation of the constructions and operation of the engine, and the present specification deals primarily with the novel starting systems and includes only sufficient description of the engine per se, and the mowing machine, to provide a complete explanation of the starting systems.

The diagrammatic illustration of another engine in FIG. 2 represents the inverse relation of piston and cylinder members with respect to the output connection, with the cylinder member 12 being supported for free movement in space relative to the piston member 10' which in turn is connected directly to the output member 17'. During operation of this configuration the cylinder member provides the solid reaction mass and the output, as shown in the drawings, is obtained from movement of the piston member.

As previously mentioned, the reaction mass member is substantially free to move within the confines of its mounting. Thus, for purposes of centering, register, or the like, the mountings for cylinder member 12 may include rubber, or like, shock mounts or bumpers 18' and may include light springs 19. For example, as the load applied at 17 is increased, the effective stroke of 10 will decrease and the effective stroke of. 12' will increase. The springs 19' will tend to maintain centering and registry, and the bumpers 18 serve as a positive means of locating member 12' in case of some abnormal movement thereof such as might result from a misfire.

An exemplary construction of an engine in accordance with the invention is shown in FIGS. 3-7, wherein a piston member 20 having a piston head 22 carrying conventional compression sealing rings 23 is provided as an integral part of a neck portion 24 of reduced diameter which is in turn integral, or suitably connected, to a larger guiding piston part 25 having enlarged annular lands 26 thereon and rearwardly projecting head 27 terminating in a pilot portion 28 of reduced diameter, providing an annular seat a 29 at the end of head 27. The piston head 22 is received within a cylinder liner or sleeve 30 which is in turn mounted in a cylinder member 32 having a plurality of suitable cooling fins 34 formed in the outer surface thereof (see FIG. and having one end thereof closed by a cylinder head member 35 (having cooling fins 36) which is bolted or otherwise secured in conventional manner across the end of cylinder 32. It is possible and conventional according to well known engine designs to have the liner A. 36, cylinder 32, and cylinder head formed as one integral part if desired.

Cylinder 32 is mounted upon an elongated preferably cylindrical body 40 having a smaller bore 42 which is 01 essentially the same internal diameter as the internal diameter of sleeve liner 30 to receive a portion of the piston head 22 during operation of the engine (see FIG. 4). The bore 42 opens into a further bore 45 of larger internal diameter and within which the guiding head 25 is received, with the lands 26 contacting the walls of bore 45 in guiding relation. The end of bore 45 is closed by head member 47 which is bolted or otherwise suitably secured to the body member 40, preferably retaining a hardened steel washer 48 therebetween, to provide an enclosed scavenging pump chamber 50 between the head member 47 and the enlarged guiding head 25 of the piston. Of course, the body construction and the head for the scavenging pump chamber may be constructed as integral parts or the body could be formed integrally with the cylinder member 32. Also, the body 40 preferably includes suitable longitudinally extending cooling fins 51.

A biasing means is provided for urging relative movement of the piston and cylinder in such directions that the parts may be in position at rest as shown in FIG. 1. One suitable form of such biasing means includes the relatively weaker return spring 52 which seats at one end on the annular surface 29, and at its other end is received within a cup-shaped guide 53 including an enlarged lip or end portion 54 which has an outer diameter slightly less than the diameter of bore 45, serving to align the cup-shaped member 53 generally within the chamber 50. The cupshaped guide includes holes 54' in the body and lip for passage of fluid therethrough which contributes to the scavenging pump action. A relatively stronger and relatively high rate return spring 55 is positioned between the lip 54 of cup member 53 and the head 47. Thus, these springs together with the cup-shaped part 53 tend to bias the piston and cylinder into the relative position shown in FIG. 3.

Further, the cup serves as a centering guide for spring 52, and prevents bottoming of that spring, and also to transmit force between these springs to reduce the shock load on spring 55 during a power stroke. Together these springs (or an equivalent biasing means) should be of sufiicient strength to transmit energy between the cylinder member and the piston member without impact therebetween during normal running conditions of the engine. The arrangement is such that spring 52 functions more as a positioning device to bias the piston toward the cylinder head 35, and to resist initial movement of the piston reacting to combustion, while the spring 55 is positioned and dimensioned to exert its biasing force essentially after relative movement of the piston and cylinder members has uncovered the ports.

Obviously, the mounting of the spring members could be reversed, with the spring 55 contacting the piston member and the cup member 53, and with the weaker return spring 52 contacting the cup member 53 and the head 47 of the scavenging pump chamber. The function of such a reversed mounting of the springs is substantially as above described.

As will be noted from the drawing, the piston 22, cylinder liner 50, and cylinder head 35 cooperate to deline a power cylinder including a combustion chamber 60, and a suitable charge igniting member such as a spark plug 62 is mounted in cylinder head 35, having electrodes 63 supported within a recess 64 in the cylinder head which is in communication with the combustion chamber.

A combustible charge is supplied to the combustion chamber through an inlet 65 providing a passage through the head member 47 into scavenging pump chamber 50, and from there the combustible fluid mixture is supplied through registering passages 68 in the walls of the main body 49 and cylinder 52 to inlet ports 76 in the cylinder liner 3%.

The forward land 26 cooperates with the larger bore 45 to define a chamber which surrounds the neck portion 24 of the piston member, and a port 72 opens through the wall of the bore 45 and is connected through passage 73 to the exterior of the main body 40. As will be noted from comparison of FIGS. 3 and 4 air is pumped via passage 73 in and out of the chamber designated generally at 74. This action will serve to circulate cooling air around the neck 24 of the piston member and further cool the parts of the engine, particularly the piston member, during operation. In action the air is expelled from port 72 in the form of a jet of relatively high velocity, and this jet may be directed to perform some auxiliary function such as blowing away cuttings or the like.

The combustible fluid mixture may be supplied to chamber 50 from a suitable charge supply device shown generally in FIG. 7. This device includes a body 75 having an internal cavity 76 which is connected through passages 78 to the atmosphere for supplying air. A reciprocable air intake check valve member 81) is seated within cavity 76 under the bias of a light spring 82 so as to close off the cavity 76 from an upper chamber 84 which is defined by the upper end of valve member 80 and a cover 85 for the body 75. An outlet tube 36 extends through cover 85 to communicate with chamber 84, and this tube 86 in turn is connected to the fitting 65 on the head member 47 of the engine. Preferably, tube 86 is made of flexible material such that there can be substantial relative movement between the engine and the charge supply device.

Fuel may be supplied from a tank 99 mounted on cover 85, and having a relatively large connecting passage 92 communicating through a restricted outlet 5&4, at the seat of valve member 89, with the air passage to the engine. The cross section of orifice 94 may be controlled through means of an adjustable valve 95, as shown in FIG. 7. Fuel flows by gravity from the fuel tank to orifice 94, and is prevented from flowing further by valve member 80 whenever that valve is seated by its spring 82. The large passage 92 provides for dispersion of any air bubbles therein into the tank, and out through the usual tank vent 96.

Assuming that the engine has been started, combustion of the compressed charge in combustion chamber as will produce relative movement between the piston member and the cylinder member such as to expand the volume of the power cylinder, and the relative movement between cylinder 32 and piston head 22 will cause the exhaust ports 16%) to be uncovered, exhausting the burned charge through these ports and exhaust passages 102 (FIG. 5) in the walls of cylinder 32 into a suitable mufiler indicated generally at 105. It will be noted that the exhaust ports ltlil extend closer to the head 35 than inlet ports 79, and therefore these exhaust ports are uncovered first as the piston and cylinder move relative to each other, thereby providing for commencing of the flow of burned products of combustion out of the cylinder before the inlet ports are uncovered.

As combustion occurs and the piston and cylinder move in such relative directions of a power stroke the volume of the scavenging pump chamber 50 is in turn decreased, and since the check valve 80 will close against reverse flow through tube 86, the charge of combustible mixture in chamber 50 is precompressed and passes through passages 68 and through the inlet ports 76, scavengine the cylinder as in conventional two-cycle practice. The scavenging system shown is of the well known reverse flow or loop type wherein the incoming charge is directed toward the cylinder wall on the opposite side from exhaust ports 1%, and also toward the cylinder head 35.

The entire engine as described above, is mounted for free movement in a direction axially of the cylinder and body 41'}. Such a mounting may be provided by connecting the cylinder head 35 and head member 47 to brackets 198 which are turn secured to a suitable output mentber 11%, shown schematically in FIG. 3, which is supported in any suitable manner for reciprocating movement parallel to the axis of the cylinder member. Thus, as the engine operates and the masses of the cylinder member and piston member react in opposite directions to combustion in the combustion chamber 60, the output member will follow the cylinder member (in the illustrated example) while the piston member will react against the biasing means to store energy therein for the following compression stroke; then as the piston returns under influence of, the spring a compression stroke will result from opposite relative movement between the piston and cylinder members.

It will be obvious to those skilled in the art that as this cycle of operations continues additional charges will be drawn into the scavenging pump chamber 5% and fed to the power cylinder through passages 68 in timed relation to relative movement between the piston and cylinder members, and that burned gases will be exhausted from the power cylinder as the exhaust ports are uncovered during travel of these members against the biasing force of the compressible means, illustrated as the springs 52 and 55.

Power is extracted from the engine by the direct connection between the mounting brackets 103 and the output member which may be suitably mounted for reciprocating movement. Obviously, the reaction of the cylinder member (which in this embodiment is connected directly to the output or load through member 110) to the combustion will produce movement of the cylinder member in one direction, and the energy stored in the spring members or biasing means will produce a powered movement of the cylinder member in the opposite direction after the energy of combustion has been dissipated. The result therefore is a reciprocating movement of the output member which may be coupled to drive any suit able element in which reciprocating movement is dc sired, as for example, a saw blade or a reciprocating cutter bar of a clipper type mowing machine.

It has been found that the amplitude of the output movement will vary between no load and relatively heavy load, but conversely the force exerted through each stroke of lesser amplitude will be increased in relation to the decrease in length of stroke. Thus in this sense the present engine provides an automatic variable trans mission of output according to conditions of load, with the force increasing as load increases, within the limits of the engine design.

As the travel of the output connected member is rev stricted, by adding load, the efiective stroke of the free or mass reaction member relative to a fixed point in space willtend to increase, thus maintaining adequate uncovering of the inlet and exhaust ports and provide non-stalling characteristics of the engine under load. Therefore'clutches or similar releasable connections between the engine and the load may be eliminated.

The foregoing description is directed to typical constructions of an engine of the present invention operating on a two-stroke cycle and employing a direct acting scavenging pump and carburetor for fuel supply. It will be obvious to those skilled in the art that either 2-cycle or 4-cycle engines may be constructed in accordance with the invention operating on either the Otto or diesel cycles, or on a combination cycle, and with suitable fuel supply apparatus, either carburetor or fuel injector ,systerns, as may be desired. The ignition systems may in corporate well known spark plug or glow plugapparatus.

and circuits, hot point ignition, or compression ignition may be employed. Other modifications will suggest themselves to those skilled in the internal combustion engine art.

The present invention is particularly directed to a novel means of starting engines of this type by producing an initial relative movement of the piston and the cylinder oneness against the biasing means, by introduction of a pressure fluid into the combustion'charnber, to uncover the inlet ports 79 and also to store sufficient energy in the biaslng means for producing a compression stroke, and also tointroduce a vaporized starting fuel into the combustion chamber. The drawings disclose two slightly different arrangements of apparatus for this purpose, but they willbe described together since the operation of each system is essentially the same.

Accordingly, referring to e165. 3, and 11, a quantity of starting fuel, preferably vaporized fuel such as propane gas is supplied from a tank 112 via tube 113, and the flow to this tube is controlled by a suitable valve 114. The starting fuel supply is then connected through a relatively small metering orifice 115 opening directly into an air supply line 11%.

Starting air under pressure is supplied from a suitable source such as the hand pump 12% (PEG. 11) which discharges through check valve 121 and past orifice 115 into a housing 122 which contains a spring closed poppet type check valve 125. In FIG. 3 this housing is shown mounted on the cylinder head and opening into a passage 127 which directs the starting charge under pressure into the combustion chamber.

In starting, the fuel valve 11 is opened for a time suflicient to fill the tube 113 with vaporized starting fuel which will be under some pressure, and the pump 12b is manipulated to supply compressed air to the valve block and thence to the combustion chamber. The starting fuel is thus mixed with air before supply to the combustion chamber. The relatively small metering orifice 115 provides sufficient restriction to flow of starting fuel from tube 113 to meter fuel into the air and produce a combustible mixture and to continue the supply of starting fuel for a number of starting strokes of the engine, since the line or tube 113 is of sufficient length to act as a fuel reservoir. This assures that the engine is kept operating until the normal charge supply system, through the scavenging pump and inlet ports 70, is sup plying fuel to the engine. At the same time, pressure due to combustion within the engine will close poppet valve 125 and prevent loss of combustion pressure, clogging of restriction 115 due to carbon deposit, or the like.

Since the starting charge is under pressure when supplied to the combustion chamber, and since relative movement of the piston and cylinder members is resisted only by the relatively light or weak spring 52 when the piston is at top dead center, the starting charge of compressed air and vaporized fuel will produce an initial relative movement between the piston and cylinder members against the biasing means. Furthermore, as the resultant combustible starting charge is ignited an initial power stroke will result and sufiicient energy will be transmitted to the biasing means to provide for return of the piston and cylinder members toward their initial position (FIG. 3) producing an initial compression stroke. As the next charge is ignited the cycle will repeat (in the case of the described two cycle engine) and the engine will then continue to operate with further charges being supplied through the normal supply system.

The orifice 115 provides proper metering of the vaporized fuel to supply a correct fuel-air mixture to the engine for starting. The length of tube 113 between this orifice and valve 114 is sufficient to maintain a supply of starting fuel during several starting strokes of the engine to insure proper starting before the supply of starting fuel in line 113 is exhausted.

Referring to FIG. 12, a suitable spark ignition system for the engines above described includes a spark plug 359 connected across the secondary winding 352 of an induction coil which also includes a primary winding 353 and a core 355. One end of the primary winding 353 is connected through a control switch 357 to a battery 358, while the other end of winding 353 is connected to a parallel circuit which includes a condenser 350 in one branch and a vibrator 36-2 having breaker contacts 363 in the other branch. The other side of this parallel circuit is connected through line 364 to the opposite terminal of battery 358. Preferably, the stationary one of the contacts 363 is mounted on an adjusting screw 366 for varying the gap between the contacts.

Operation of this type of an ignition system is well known, with the arm 362 being vibrated by attraction to the core 355 when a circuit is completed through the primary winding, this serving to break the primary circuit and to induce a sharp pulse in the secondary winding and across spark plug 35 At the same time, the spring arm 3-67 is released, returning the contacts into engagement. Practical experience has shown that a timed spark is not necessary to satisfactory operation of the engine, and that the above described system is satisfactory. However, if a timed spark is desired it can be provided by known means.

If desired, a simple glow plug circuit such as shown in FIG. 13 also may be used, wherein a glow plug 376 including a glow wire 372 is used in place of the spark plug, and the wire is brought to incandescent temperature by imposing an electrical potential thereacross from battery 375, with the circuit being controlled by a switch 37 Of course, other suitable known types of ignition may be used. For example, it is possible to provide a hot spot in the combustion chamber which will become incandescent from the heat of combustion and retain sufiicient heat to remain incandescent and ignite a charge during the following cycle of operation. Such a technique is well known in the internal combustion engine art. Also, it is possible with a suitable type of glow plug, as mentioned above, to disconnect the electrical circuit to the glow plug once the engine is running, and to have the glow wire 372 remain incandescent and function as the aforementionec hot spot.

FIGS. 8 and 9 disclose a typical application of an engine such as described in the foregoing parts of this specification, wherein the reciprocating output of the mass reaction engine is coupled directly to the cutter bar of a clipper type mowin machine. The machine includes main side frame members 4% connected by a cross member 4411, and having downwardly extending legs 402 secured to the rearward ends thereof providing inverted generally V-shaped side members. A forward axle 405 extends through the foremost lower ends of frame members 4th? and carries front wheels 4% at its outer ends. Similarly, a rear axle 407 extends between the lower ends of legs 4&2 and supports rear wheels 4G3 at the outward ends thereof. Any suitable means to adjust the axles with respect to the frame can be provided to adjust the cutting height. A cross-bracket or shelf 412-, of generally L-shape in side elevation, is secured between the frame members 469 proviidng support for auxiliary apparatus.

such as the battery, control valves, starting fuel tank, the fuel supply and carburetor, and similar parts not directly carried on the engine.

At the forward end of frame members 46%) there are fixed upwardly extending brackets 415 which carry a pair of guide rods 420 therebetween. Mounting plates 422 are slidably received on rods 420, and include suitable mounting bolts 423 which may be secured to the head members 35 and 47 of the engine, thus providing a free support for reciprocation of the engine in a directron parallel to its longitudinal axis.

The lower ends of frame members 489 are suitably flattened and secured, as by welding, to a lower sta tionary mounting plate or bar 430 upon which is supported a stationary cutter bar 432 having a plurality of forwardly extending cutter teeth 435 which function in normal manner to guide the grass or other material being mowed rearwardly into the cutters. On top of stationary cutter bar 432 is a slidably supported cutter bar 440 having shorter forwardly projecting teeth 442 above each of the stationary teeth 435, and cooperable therewith to provide cutting elements for shearing off grass or the like as these teeth move relative to each other. The stationary pressure plate 445 extends over movable cutter bar 440 and is positioned on the cutter bar assembly through Belleville type springs 447. The movable cutter bar 440 is provided with slots 44% (FIG. 8) through which bolts 446 extend, defining the direction of relative movement between the movable and stationary cutter bars.

The rearward edge of the upper pressure plate 445 includes a pair of elongated notches 449 which are generally aligned with the side frame members 400, as shown in FIG. 8. Connecting brackets 450 are secured as by welding to a movable cutter bar 440 centrally of these notches, and extend upwardly to the elevation of the support rods 420 and then inwardly to the mounting plates 422. Bracket 459 includes slots 452 within which the forward ends of plates 422 are received, providing a drive connection therebetween. This construction atfords a semi-flexible connection between the engine and cutter bar 440, so that engine movements which might not be in precise alignment with movement of the cutter bar will not be transferred to the cutter bar and disturb its cutting function.

Thus, reciprocating movement of the engine cylinder member produces corresponding reciprocation of movable cutter bar 440. This particular construction of connecting brackets 450 aligns the vertical parts thereof with the frame members 400, thus reducing to a minimum the area of interference of parts extending upwardly behind the cutters, and facilitating the flow of cuttings over the cutter bars.

The handle structure for the mowing machine in cludes a hollow handle bar 460 which also may provide the cylinder of a manually operable air pump, there being a piston cup 462 received in the handle and connected to an elongated rod 463 which projects upwardly through the mounting plate 465 at the top of handle cylinder 460, having a grip 466 at the upper end thereof. This structure may provide the starting air pump 120.

The only vibration ordinarily transmitted to the frame of the mower will be that due to resistance to relative movement in the motor mounts and between the stationary and moving cutter bars. However, the handle cross bar 470 extends from the lower end of handle 460 and may include conventional Lord shock mounts 472 at opposite ends thereof secured to the frame members 402 I to provide isolation of the handle from vibration of the frame. Supporting arms 475 extend downwardly from the cross bar 470 and are secured at their lower ends to similar shock mountings 477. Details of these shock mountings are shown in said parent application.

A suitable device is provided for maintaining the teeth of the moving and stationary cutter bars in properregister, as for example, in the event that the engine should misfire and the resultant movement in one direction might be greater than in the opposite direction. This I mechanism is disclosed in detail in FIG. 9 as including a rod 560 threaded over substantially the entire surface and extending through suitable aligned holes 502 in the head of the engine and in the mounting plate 422. A pair of lock nuts 505 is provided on each side of the mounting bracket and head to define the limits between which the cylinder member of the engine can reciprocate. Rod includes a reduced end 507 which is retained in the flexible shock absorbing member 510 of a suitable shock mount, for example a Lord shock mount as mentioned previously, having a mounting cup 512. This cup in turn is supported upon a bracket 514 which is secured, as by welding 515 to the side frame member 400 of the mowing machine.

The invention also includes a novel self-starting arrangement for engines of the type herein disclosed, which may be used particularly in mowing machines or the like as above described. Referring to FIG. 14, wherein parts valve 148'.

. 10 similar to the starting system shown in 17 are designated with like reference numerals having a prime added, the engine embodies suitable compressor structure as disclosed in said parent application, for example for coupling into the passage 73, and discharges through line 15% into an air reservoir or tank 525 through the check This tank in turn has an outlet line 527 leading to a two-way valve 530 which is connected, as shown, in the supply line 118' between hand pump 120T and the mixing T through which starting fuel from tank 112 is added. Thus, by appropriate manipulation of valve 530 the line 527 from compressed air tank 525- may be connected to line 118' and used as a source of starting pressure fluid for supplying a combustible mixture to the engine. In the event that for some reason there is not sufficient pressure in tank 525, the valve 530 may be turned to the position illustrated for supply of compressed air from the hand pump Valve 114 is normally closed, and may be remotely controlled by a spring biased operating cable 540 having a control knob 542 on the mounting plate 465, such that a momentary push on the knob will release a quantity of propane to the T 115'. Valve 530 is normally in the position shown in FIG. 14, and may be remotely actuated through a spring biased cable 545 having a knob 547 on plate 465. Thus, momentary actuation of cable 545 will release a quantity of compressed air from tank 525 into line 118. Also, switch 357 may conveniently be mounted on plate 465, such that all the starting controls are centrally located adjacent the handle cross bar 550.

The invention provides novel apparatus for starting internal combustion engines, particularly of the type herein disclosed, which assures starting under all types of conditions. The starting fuel charge supplied to the engine is vaporized, thus minimizing one of the dificulties in starting (particularly in two cycle engines) which may result from inadequate vaporization of fuel charges supplied during starting. 'As is well known, during cold starting with liquid fuel a rich (excess liquid) mixture is required due to the difliculty of obtaining proper vaporization, and flooding may result, with consequent inability to start the engine.

Furthermore, a mowing machine incorporating the novel starting features disclosed herein is relatively easy to start and requires substantially no effort on the part of the operator, While at the same time not requiring any outside connections, as to a source of electricity or external starting mechanism.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. Apparatus for starting an engine having a cylinder and a piston freely movable relative to each other and normally resiliently bliased in a direction to reduce the volume of the power cylinder formed therebetween, said engine having charge introduction means for supplying combustible charges to said power cylinder during normal operation of said engine, comprising a source of vaporized starting fuel, a source of air under sufficient pressure to produce relative movement between said piston and said cylinder against the normal bias thereon, means connected to supply starting fuel and compressed starting air from said sources to said engine independently of said normal charge introduction means and in quantities proper to form a combustible starting charge, means for igniting said starting charge in said chamber to initiate self-sustaining operation of said engine, and means between said starting fuel supply source and said starting charge supply means for maintaing the supply of starting charges during several starting strokes of said engine.

2. In a mowing machine having a frame movable over ii a the ground and carrying a cutter driven by an internal combustion engine, starting apparatus for said engine comprising an air compressor operable by said engine, a compressed air reservoir connected to store air under pressure from said compressor, a starting fuel tank containing a quantity of vaporized starting fuel, means mounting said tank and said reservoir on said frame, conduit means connected between said compressed air reservoir and the combustion chamber of said engine for supplying a starting charge to said engine independently of the normal charge supply thereto, means metering vaporized fuel from said tank into said conduit means to form a starting charge for said engine, and control means connected to govern the supply of starting charges to said engine. V

3. In a mowing machine having a frame movable over the ground and carrying a cutter driven by an internal combustion engine, starting apparatus for said engine comprising an air compressor'operable by said engine, a compressed air reservoir connected to store air under pressure from said compressor, a starting fuel tank containing a quantity of vaporized starting fuel, means mounting said tank and said reservoir on said frame, conduit means connected between said compressed air reservoir and the combustion chamber of said engine for supplying a starting charge to said engine independently of the nor- 7 mal charge supply thereto, means for metering vaporized fuel from said tank into said conduit means to form a starting charge for said engine, control means connected to govern the supply of starting charges to said engine, a manual air pump, and means for selectively connecting said air pump and said reservoir to said conduit means.

4. In combination with a free piston engine having a cylinder and a piston freely reciprocable therein and defining therewith a power cylinder including a combustion chamber, resilient biasing means acting between said piston and said cylinder and having sufiicient strength to provide for reversal of direction of relative movement therebetween after combustion of a charge in said chamber, and means supplying combustible charges to said power cylinder during normal operation of said engine; the improvement comprising a starting system including a source of air under pressure sufficient to produce relative movement between said piston and said cylinder against the force of said biasing means, a source of vaporized starting fuel independent of said charge supply means, means connecting said air source and said starting fuel source for producing a combustible starting charge, means for introducing said starting charge into said combustion chamber independently of said normal charge supply means, and means arranged to ignite said starting charge in said chamber to initiate operation of said engine. I

5. Apparatus as defined in claim 4 wherein said starting air source includes a manually operable pump, and wherein said source of starting fuel comprises a container of fuel which is gaseous at normal atmospheric pressure and which is stored in said container under suficient pressure to cause flow of said starting fuel therefrom, a selectively operable valve connected to control the flow of said starting fuel from said container into said source of starting air, and check valve means incorporated in said means introducing said starting charge into the compustion chamber for preventing reverse fiow of gases from said combustion chamber through said introducing means.

References flied in the file of this patent UNITED STATES PATENTS 573,958 Bates Dec. 29, 1896 2,031,535 Kiecksee Feb. 18, 1936 3,023,563 Tenney Mar. 6, 1962 FOREIGN PATENTS 115,806 Sweden Feb. 5, 1946 

1. APPARATUS FOR STARTING AN ENGINE HAVING A CYLINDER AND A PISTON FREELY MOVABLE RELATIVE TO EACH OTHER AND NORMALLY RESILIENTLY BLIASED IN A DIRECTION TO REDUCE THE VOLUME OF THE POWER CYLINDER FORMED THEREBETWEEN, SAID ENGINE HAVING CHARGE INTRODUCTION MEANS FOR SUPPLYING COMBUSTIBLE CHARGES TO SAID POWER CYLINDER DURING NORMAL OPERATION OF SAID ENGINE, COMPRISING A SOURCE OF VAPORIZED STARTING FUEL, A SOURCE OF AIR UNDER SUFFICIENT PRESSURE TO PRODUCE RELATIVE MOVEMENT BETWEEN SAID PISTON AND SAID CYLINDER AGAINST THE NORMAL BIAS THEREON, MEANS CONNECTED TO SUPPLY STARTING FUEL AND COMPRESSED STARTING AIR FROM SAID SOURCES TO SAID ENGINE INDEPENDENTLY OF SAID NORMAL CHARGE INTRODUCTION MEANS AND IN QUANTITIES PROPER TO FORM A COMBUSTIBLE STARTING CHARGE, MEANS FOR IGNITING SAID STARTING CHARGE IN SAID CHAMBER TO INITIATE SELF-SUSTAINING OPERATION OF SAID ENGINE, AND MEANS BETWEEN SAID STARTING FUEL SUPPLY SOURCE AND SAID STARTING CHARGE SUPPLY MEANS FOR MAINTAINING THE SUPPLY OF STARTING CHARGES DURING SEVERAL STARTING STROKES OF SAID ENGINE. 